How will you tell him that you wanted to go on with the relationship?

It is as easy as it seems, but my bf will soon (in less than a month) move 3 hrs. away from where I am and it would be temporarily impossible for him to travel and see me because he will have a foot surgery and needs to heal and it would take 3 weeks or even months. This is not just a simple one, but an amputation. I wanted to tell him that I will do everything I can just to keep on seeing him. I am 5 mos. pregnant and I know I have to consider my condition too. I just don't know how I can tell him that I will stay in touch with him and continue to see him. We've been going out for 4 months now and I see a future with him eventhough his condition is a difficulty for us to spend time together. I saw how much he cares for me and his efforts to see me during the week and the weekends and how he show that I am special. He just doesn't tell me, but I know in his actions, he wants me to stay and I just don't know how I would tell him that no matter what happens I will be with him.